Method and apparatus for real-time mechanical and dosimetric quality assurance measurements in radiation therapy

ABSTRACT

A method and device for real-time mechanical and dosimetric quality assurance measurements in radiation therapy provides a unified measurement of mechanical motion and radiation components of the machine. The device includes an imaging surface for receiving multiple energy sources. The imaging surface has an imaging plane positioned on a same plane as an isocenter of a medical accelerator. A camera measures and records data related to the multiple energy sources. A mirror system can be used to direct the multiple energy sources to the camera for further processing. However, in some instances the mirror system may not be necessary. Accordingly, a single device can be used to unify the measurement of mechanical motion and radiation component of the machine. The device can also include computer control in order to automate the movement of the device and/or automation of the QA protocol.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is Continuation of International ApplicationPCT/US2013/029775 having an international filing date of Mar. 8, 2013,which claims the benefit of U.S. Provisional Application No. 61/608,300,filed Mar. 8, 2012, the content of each of the aforementionedapplications is herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to radiation therapy. Moreparticularly the present invention relates to mechanical and dosimetricquality assurance in radiation therapy.

BACKGROUND OF THE INVENTION

Medical accelerators are used for radiation treatment of cancer patientsand emit radiation in 360°. A patient lies on a platform, while a headof the device is rotated around the body of the patient. Qualityassurance (QA) of the integrity of the medical accelerators is paramountto ensure the safe delivery of radiation treatment. The two maincriteria used for QA is radiation reproducibility and mechanicalintegrity of the machine. The QA tasks specifically consist ofquantifying the accuracy and precision of mechanical motions of theaccelerators, various optical indicators, and the delivered dosimetry.FIG. 1 illustrates a chart of QA tasks per medical accelerator that mustbe performed daily, monthly, and annually.

FIG. 2 illustrates a front view of a medical accelerator used forradiation treatment. As illustrated in FIG. 2, one task of QA is toensure that radiation beams along an axis and the positioning aids, inthe form of laser beams, align at an isocenter of the medicalaccelerator. QA of this alignment is important in order to verify thatthe radiation beams along axis 1 are configured to treat the patientaccurately without causing burns or other undesired side effects.

At present, almost all of the QA tasks listed in FIG. 1 are performedwith different apparatus. The mechanical and optical components areexamined visually, where the data is not amenable to documentation. Forexample, a technician checks the light source by directing the sourceonto the patient couch, and rotating it to make sure it moves about theisocenter of the medical accelerator. The dosimetry is measured with avariety of ionization detectors with the two-dimensional array ofdiscrete detectors being most popular. Higher resolution measurementsare measured with films where the data conversion process can betedious. Some of these tasks are performed on a daily, monthly or yearlybasis, and can take hours to perform. For example, while dailymaintenance only takes approximately 10 minutes, a monthly maintenanceof such machines to test the output and the mechanical integrity of themachine typically will take between 5-6 hours, the results of thetesting partially documented. In fact, annual maintenance on the machinecan take approximately 4 days to complete.

Accordingly, there is a need in the art for a device that provides afaster and more accurate measurement of the QA of the integrity ofmedical accelerators. In addition, there is a need in the art for asingle device that measures both mechanical and dosimetric QA tasks andproduces documentable results regarding the QA measurements.

SUMMARY

According to a first aspect of the present invention a device forunifying real-time mechanical and dosimetric quality assurancemeasurements in radiation therapy includes an imaging surface forreceiving multiple energy sources. The imaging surface is positioned ona same plane as an isocenter of a medical accelerator. The deviceincludes a camera for measuring and recording data related to themultiple energy sources. Additionally, the device includes a mirrorsystem for directing the multiple energy sources to the camera. Themirror system is also configured to maintain an imaging plane of thecamera at the isocenter of the medical accelerator.

In accordance with an aspect of the present invention, the camera isstationary and positioned to be on the same axis as the imaging plane. Acomputer system is included for collecting and analyzing the data. Thecomputer system can include a feedback loop for automatic control of thedevice. Measurements are made in real-time. The mirror system includesno mirrors or one or more mirrors for directing the energy sources tothe camera. If mirrors are used the mirrors can be fixed or movable.Additionally, the imaging surface is rotatable about an axis of thecamera. A single phosphor screen or plastic scintillator sheet is usedfor receiving multiple energy sources from x-ray, electron, light andlaser beams. The phosphor screen or plastic scintillator sheet includemarkings for spatial calibration.

In accordance with another aspect of the present invention, the mirrorsystem is rotatable to capture data from different gantry angles. Thedevice can be programmed to move in synchrony with mechanical componentsof the medical accelerator about the isocenter. The camera can take theform of a conventional camera. In such a case, a mirror is arranged toshield the camera from radiation. Alternately, the camera takes the formof a radiation resistant camera. The camera can also take the form of aflat panel detector. A computing device can be configured to control themovement of the device, and the computing device is programmed toautomate a QA protocol to be executed using the device. In addition, thecomputing device is configured to automate the movement of the device inconjunction with a movement of the medical accelerator. At least onesheet of plastic water can be included, and the at least one sheet ofplastic water can accommodate an ion chamber. The at least one sheet ofplastic water can also include a receptor for the ion chamber drilledinto the at least one sheet of plastic water at a 45° angle.

In accordance with another aspect of the present invention, a method forreal-time mechanical and dosimetric quality assurance measurements inradiation therapy, includes providing an imaging surface for receivingmultiple energy sources. The imaging surface includes an imaging planepositioned on a same plane as an isocenter of a medical accelerator. Themethod also includes directing the multiple energy sources to a camera.Data related to the multiple energy sources can be measured andrecorded.

In accordance with yet another aspect of the present invention, theimaging surface can take the form of a phosphor screen configured toreceive all optical light, laser light, and radiation signals. A digitalsensor is configured to remain stationary with respect to the phosphorscreen. The optical light, laser light, and radiation signals aredirected to the phosphor screen via an optical path. Additionally, theoptical path further includes mirrors configured to direct the opticallight, laser light, and radiation signals to the phosphor screen.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings provide visual representations which will beused to more fully describe the representative embodiments disclosedherein and can be used by those skilled in the art to better understandthem and their inherent advantages. In these drawings, like referencenumerals identify corresponding elements and:

FIG. 1 illustrates a chart of QA tasks per medical accelerator that mustbe performed daily, monthly, and annually.

FIG. 2 illustrates a front view of a medical accelerator used forradiation treatment.

FIG. 3A illustrates a perspective view of a device according to thefeatures of the present invention sitting within the treatment range ofa medical accelerator. FIG. 3B illustrates a perspective view of adevice according to the features of the present invention sitting withinthe treatment range of a medical accelerator. FIG. 3C. illustrates aperspective view of a device according to the features of the presentinvention sitting within the treatment range of a medical accelerator.FIG. 3D illustrates a perspective view of a device according to thefeatures of the present invention sitting within the treatment range ofa medical accelerator.

FIG. 4A illustrates a partially top-down perspective view of a devicefor real-time mechanical and dosimetric quality assurance measurementsin radiation therapy according to the features of the present invention.FIG. 4B illustrates a perspective view of a device for real-timemechanical and dosimetric quality assurance measurements in radiationtherapy according to the features of the present invention. FIG. 4Cillustrates a perspective view of a rotated device for real-timemechanical and dosimetric quality assurance measurements in radiationtherapy according to the features of the present invention.

FIG. 5A illustrates a partially sectional perspective view of a devicefor real-time mechanical and dosimetric quality assurance measurementsin radiation therapy according to the features of the present invention.FIG. 5B illustrates a partially sectional perspective view of a devicefor real-time mechanical and dosimetric quality assurance measurementsin radiation therapy according to the features of the present invention.FIG. 5C illustrates a partially sectional perspective view of a devicefor real-time mechanical and dosimetric quality assurance measurementsin radiation therapy according to the features of the present invention.FIG. 5D illustrates a partially sectional perspective view of a devicefor real-time mechanical and dosimetric quality assurance measurementsin radiation therapy according to the features of the present invention.

FIG. 6 illustrates a side view of a QA device according to an embodimentof the present invention.

FIG. 7 illustrates a diagram of a method according to the features ofthe invention.

FIGS. 8A and 8B illustrate schematic diagrams showing a method accordingto the features of the invention. Note that the laser image has neverbeen captured with prior art of QA devices.

FIG. 8C illustrates a method of performing table positioning QA,according to an embodiment of the present invention. Note that the lightfield image with the optical distant indicator has never been capturedwith prior art of QA devices.

FIG. 8D illustrates a method of performing rotation QA as capturedoptically for documentation, according to an embodiment of the presentinvention.

FIG. 8E illustrates a method of performing optical and radiationcoincidence of a field shaped by the multi-leaf collimator.

FIG. 9 illustrates a hard coded digital image scale, according to anembodiment of the present invention.

FIG. 10 illustrates an analysis tool, provided by the software controlprogram for the device of the present invention.

FIG. 11 illustrates a localization tool, provided by the softwarecontrol program for the device of the present invention.

FIG. 12 illustrates a region of interest tool, provided by the softwareprogram for the device of the present invention.

FIG. 13 illustrates an exemplary screen for defining scale in anacquired image taken using the device of the present invention.

FIG. 14A illustrates an example of a program feature to superimposeimages taken with the device of the present invention.

FIG. 14B illustrates an example of an image for analysis of co-linearityof the laser taken using the device of the present invention.

FIG. 15 illustrates an image of an exemplary recording of laser QA tasksexecuted with the device of the present invention.

FIG. 16A illustrates an image of an exemplary recording of laser QAtasks executed with the device of the present invention. FIG. 16Billustrates an image of an exemplary embodiment of the user interfaceshowing the acquisition of a right room laser QA.

FIG. 17 illustrates an image of an exemplary recording of laser QA tasksexecuted with the device of the present invention.

FIG. 18 illustrates an image of an exemplary recording of laser QA tasksexecuted with the device of the present invention.

FIG. 19 illustrates laser alignment analysis using the device of thepresent invention.

FIG. 20 illustrates laser alignment analysis using the device of thepresent invention.

FIGS. 21A-F, 22A-F, and 23A-C illustrate exemplary recordings of tablemovement and optical distance indicator (ODI) QA tasks executed with thedevice of the present invention. More particularly, FIGS. 21A-F relateto QA for table vertical movements captured using the device of thepresent invention, FIGS. 22A-F relate to QA for table lateral movementsexecuted with the device of the present invention, and FIGS. 23A-Cillustrates visual results of table rotation QA, using the device of thepresent invention.

FIGS. 24A-D illustrate collimator rotation QA, using the device of thepresent invention.

FIGS. 25A and 25B illustrate the visual results of radiation and lightfield congruence QA, using the device of the present invention. FIG. 25Cillustrates an exemplary embodiment of the user interface showing theacquisition of a 6 MV x-ray QA, as described with respect to FIGS. 25Aand 25B. FIG. 25D illustrates another example of a light field andradiation field congruence image acquired using the device of thepresent invention.

FIG. 26 illustrates a graph obtained using a profile tool in the controlprogram for the device of the present invention.

FIGS. 27A and 27B, 28A and 28B, FIG. 29 and FIGS. 30A and 30B illustratevisual representations of radiation field acquisition and analysis. Moreparticularly, FIGS. 27A and 27B illustrate exemplary plots to showcalculation methods for determining photon beam flatness and symmetryusing a 1D plot, FIGS. 28A and 28B illustrate visual representations ofradiation measurements taken using the device of the present invention,FIG. 29 illustrates a visual representation of a mean radiation image,taken using the device of the present invention, and FIGS. 30A and 30Billustrate exemplary visual representations of energy checks forradiation analysis.

FIGS. 31, 32A-B, and 33A-B illustrate visual representations andanalysis of multi-leaf collimator (MLC) QA measurements, taken using adevice of the present invention.

FIGS. 33A and 33B illustrate visual representations of measurement andanalysis for leaf speed of the MLC.

FIG. 34 illustrates a schematic diagram that the QA device of thepresent invention can accommodate the measurements of absolute dosimetrywith an ionization chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The presently disclosed subject matter now will be described more fullyhereinafter with reference to the accompanying Drawings, in which some,but not all embodiments of the inventions are shown. Like numbers referto like elements throughout. The presently disclosed subject matter maybe embodied in many different forms and should not be construed aslimited to the embodiments set forth herein; rather, these embodimentsare provided so that this disclosure will satisfy applicable legalrequirements. Indeed, many modifications and other embodiments of thepresently disclosed subject matter set forth herein will come to mind toone skilled in the art to which the presently disclosed subject matterpertains having the benefit of the teachings presented in the foregoingdescriptions and the associated Drawings. Therefore, it is to beunderstood that the presently disclosed subject matter is not to belimited to the specific embodiments disclosed and that modifications andother embodiments are intended to be included within the scope of theappended claims.

The present invention pertains to a method and apparatus for real-timemechanical and dosimetric quality assurance measurements in radiationtherapy. According to an exemplary embodiment as shown in FIGS. 3A-3D, asingle unifying device can be employed to perform all mechanical anddosimetric QA tasks, thereby greatly simplifying and unifying all QAtasks. The use of a digital camera ensures that all measurements can bedocumented for repeat analysis. As such, data can be captured inreal-time in one session. In addition, the system can be integrated withthe operation of the radiation machines to automate the entire process.The data can be analyzed in real-time or off-line to provide alertsabout or to trend the performance of the machine in relationship withthe treatment room. Accordingly, the method and apparatus of the presentinvention unifies measurement of mechanical motion and radiationcomponent of the machine.

FIGS. 3A-3D show the operation principles of the system. In FIGS. 3A-3D,the device 10 is placed on the patient couch 12 of the radiationtreatment room. The device 10 is positioned adjacent to a medicalaccelerator 14 to undergo QA measurements, such that the device 10 ispositioned between jaws 16, 18 of the medical accelerator 14 including amultileaf collimeter (MLC) 24 and a gantry 26. When placed on the couch12, the device 10 can be rotated continuously from approximately +90° to−90°, so as to view the radiation or optical images of the gantry 26 asit rotates from approximately +90° to −90°. The device can also berotated a full 360°, when it is supported to suspend off the edge of thecouch. FIG. 3A illustrates the jaws 16, 18, the gantry 26, and the MLC24 in an intermediate position between approximately 0° and 90°. FIG. 3Billustrates the jaws 16, 18, the gantry 26, and the MLC 24 in a positionat approximately −90°. FIG. 3C illustrates the jaws 16, 18, the gantry26, and the MLC 24 in a position at approximately 0°, and FIG. 3Dillustrates the jaws 16, 18, the gantry 26, and the MLC 24 in a positionat approximately 90°.

Also, as illustrated in FIGS. 3A-3D, for radiation QA measurements,including complex intensity modulated treatment, an imaging surface 22for receiving multiple energy sources will be used. The imaging surface22 can take any form known to one of skill in the art for receiving themultiple energy sources. More particularly, a phosphor screen or ascintillator sheet can be used to capture the multiple energy sources.The phosphor screen is also used for optical imaging of light fields,optical indicator, and laser paths. The imaging surface 22 can alsoinclude markings to show spatial calibration. By placing the device in aposition not obstructed by the treatment head 20, the system can be usedto capture optically the positions of all lasers and other alignmentindicators in the room, as well as the integrity of mechanical motionsof the medical accelerator 14 including jaws 16, 18, MLC 24, gantry 26,and couch 12. This is a major improvement since these opticalmeasurements are currently visually noted and recorded as texts in theQA document. The use of a common phosphor screen or scintillator sheetfor both radiation and optical imaging is also an important, yet to bereported in the ART, discovery, because it renders un-necessary thereplacement of the phosphor screen for optical imaging.

FIGS. 4A-4C illustrate views of the device 10 in further detailaccording to the features of the present invention. FIG. 4A illustratesa perspective view of a first side of the device 10, while FIG. 4Billustrates a perspective view of a second side of the device 10, bothaccording to the features of the present invention. FIG. 4C illustratesa perspective view of the device rotated to a position of about −45°. Asillustrated in FIGS. 4A-4C, the device 10 includes a housing 21 and acamera 28. The camera can take the form of a conventional digital cameraor a radiation resistant camera. It should be noted that if aconventional digital camera is used a shield, described further herein,can be used to protect the camera from radiation and to lower theoverall cost of the device from a model including a radiation resistantcamera. The camera 28 is further configured to measure and record datarelated to multiple energy sources used in radiation therapy. The camera28 also includes a lens 29. In order to divert data from the multipleenergy sources to the camera 28, at all medical accelerator 14 gantry 26angles, the device 10 also includes a mirror system 30. The mirrorsystem 30 includes an internal three-mirror arrangement that will bedescribed in further detail with respect to FIGS. 5A-5D. While athree-mirror arrangement is shown here as an exemplary embodiment, anyfunctional mirror system could be used as long as it maintains astationary camera position while the receptor phosphor screen rotatesabout the isocenter plane of the accelerator 14 gantry 26.

Further, as illustrated in FIGS. 4A-4C, the device 10 is mounted on arotary table 34. The rotary table 34 allows for the device 10 to berotated between approximately −90° and 90° such that the imaging surface22 and the mirror system 30 can remain aligned with the gantry 26 torecord data. The rotary table 34 can also include a base support 36. Thebase support 36 includes leveling feet 38 and a bubble level 40. Theleveling feet 38 and the bubble level 40 allow for the device 10 to beleveled for optimal operation, when placed for a QA analysis of amedical accelerator. The rotary table 34 can also include arms 42, 44,which hold and suspend the device 10, slightly above a top surface 46 ofthe base support 36. This allows the device 10 to rotate freely about anaxis “A” of the rotary table 34. The mechanism for rotation can take theform of any suitable mechanism for rotating the device 10 fromapproximately −90° to 90°. In another embodiment, the entire base can bedesigned to rotate with the arms 42, 44 and device 10, such that themeasurements can be acquired in full 360° rotation.

FIGS. 5A-5D shows the internal three-mirror arrangement 30 which can berotated to capture data from different gantry angles. This three-mirrorarrangement 30 within housing 21 allows the placement of the image plane48, i.e., the imaging surface 22, at the plane of the machine isocenter50 which is the calibration center of all machine parameters. Mostimportantly, the camera 28 is stationary and positioned to be on thesame axis as the imaging plane. As such, the image plane 48 is co-linearwith an axis “B” through the longitudinal center of the camera 28.Additionally, the image plane 48 can be rotatable about the axis “B” ofthe camera 28. It should also be noted that the camera 28 can be keptstationary while the device 10 rotates about the camera 28.

Further, as illustrated in FIGS. 5A-5D, a first mirror 52 is positionedon a first lower wall 54 of the housing 21 of the device 10, across fromthe camera 28. A second mirror 56 is positioned on a second lower wall58 of the housing 21 of the device 10 and adjacent to the first mirror52 positioned on the first lower wall 54. The first mirror 52 and thesecond mirror 56 are separated by an angle. Any suitable angle ofseparation can be used so long as the data is properly transmitted tothe camera 28. A third mirror 60 is positioned in a first plane parallelto a second plane in which the second mirror 56 is disposed. The firstplane is separated from the second plane by a distance. The distance canbe any distance suitable for transmitting the data to the camera 28.Preferably, all mirrors are set at 45 degree to allow 90 degreereflection. This is not a necessary requirement, as robotics can be usedto provide 90 degree reflection, or software can be used to correctimperfect reflection.

Generally, data from the treatment head 20 is transmitted along atrajectory path 68. Trajectory path 68 travels perpendicularly throughthe imaging surface 22 and reflects off of the first mirror 52 at anapproximately 90° angle. Preferably, the angle will be exactly 90°.Imperfect 90° will be corrected by software. The trajectory path 68 thentravels across an interior space 70 defined by walls of the device 10 tobe reflected off of the second mirror 56 at an approximately 90° angle.The trajectory path 68 then continues vertically to be reflected off ofthe third mirror 60 at an approximately 90° angle. After being reflectedoff of the third mirror 60, the trajectory path 68 continues on throughthe lens of the camera 28 for recording of the data travelling along thepath 68. While a specific mirror system is described above, this exampleis not meant to be limiting. Indeed, the mirror system can be configuredsuch that it has one or more stationary or adjustable-position mirrorsor a combination thereof. Additionally, the mirror system can berotatable in order to capture data from different gantry angles.

Also, as illustrated in FIGS. 5A-5D, as the device rotates, thethird-mirror directs all data from the image plane to the camera. Thecamera can be held stationary to capture any rotated views that can bedigitally corrected or the camera can be rotated in its stationaryposition with the mirror subsystem so that no image correction isneeded. The stationary camera offers advantage in the simplicity of setup. A computer can also be included in the system for collecting andanalyzing the data. The computer includes a feedback loop for automaticcontrol of the device 10. More particularly, the device 10 can beprogrammed to move in synchrony with mechanical components of themedical accelerator about the isocenter. Measurements are made in realtime. The system can be extended for QA of the kilovoltage imagingsystem, as well as the positioning of radioactive sources inbrachytherapy. Software tools can be implemented to analyze, evaluateand trend the performance of the treatment unit and the integrity ofin-room alignment accessories.

FIG. 6 illustrates a partially sectional view of a QA device accordingto an embodiment of the present invention. As described above withrespect to FIGS. 5A-5D, FIG. 6 illustrates a partially sectional view ofthe device 100. An embodiment of the internal mirror arrangement 130 isillustrated, within housing 121. The internal mirror arrangement 130allows the placement of the image plane 148, i.e., the imaging surface122, at the plane of the machine isocenter.

Further, as illustrated in FIG. 6, a first mirror 152 is positioned on afirst lower wall 154 of the housing 121 of the device 100. A secondmirror 156 is positioned on a second lower wall 158 of the housing 121of the device 100 and adjacent to the first mirror 152 positioned on thefirst lower wall 154. The first mirror 152 and the second mirror 156 areseparated by an angle. Any suitable angle of separation can be used solong as the data is properly transmitted to the camera. A third mirror160 is positioned in a first plane parallel to a second plane in whichthe second mirror 156 is disposed. The first plane is separated from thesecond plane by a distance. The distance can be any distance suitablefor transmitting the data to the camera. The device can also include afourth mirror 172 positioned, such that it shields the camera fromdirect radiation from the medical accelerator. The fourth mirror 172 isalso positioned at an angle such that the data is transmitted from thethird mirror 160 to the camera.

FIG. 7 illustrates a diagram of a method in accordance with the featuresof the invention. The method 200 is directed generally to real-timemechanical and dosimetric quality assurance measurements in radiationtherapy. The method 200 includes a step 202 of providing an imagingsurface for receiving multiple energy sources. More particularly, theimaging surface has an imaging plane positioned on a same plane as anisocenter of a medical accelerator. Step 204 includes directing themultiple energy sources to a camera. Additionally, step 206 can includemeasuring and recording the data related to the multiple energy sources.

FIGS. 8A and 8B further illustrate methods of assessment of two of themany QA criteria to be performed on a medical accelerator, in accordancewith the features of the invention. As shown in FIGS. 8A and 8B,multiple energy sources can be directed at the device 300, and can thusbe recorded by the device 300. In FIG. 8A, a radiation beam 308 from themedical accelerator 304 is directed at the device 300. The radiationbeam 308 is directed at the device 300, such that it travels through theimaging surface 322, in this case a phosphor screen. The light 309 fromthe phosphor screen can then be measured by the camera 328, as shown insample image 310. The camera 328, can then transmit the data to computer312 for recording and analysis, either through a wired or wirelessconnection. In FIG. 8B, room lasers 314, 316 at isocenter plane can bedirected at an imaging surface 322 of the device 300. The phosphorscreen can also be used as the image receptor 318 at the imaging plane322 with an overlaying scale 320 or a digitally encoded scale. Theprojection of the room lasers 314, 316 is measured by the camera 328,and the data can then be transmitted to a computer (not pictured) forrecording and analysis.

FIG. 8C illustrates a method of performing table positioning QA,according to an embodiment of the present invention. Previously, tablepositioning QA was measured visually. Optical Distance Indicator (ODI)verification is used, which is a verification of a lateral laser. Thelaser, which mimics the source of radiation, is shined onto the deviceof the present invention, which is disposed on the patient table androtated 90° to view the lateral room laser. The correctness of thepositioning of the laser was previously assessed visually, and norecording of the positioning could be made. Using the device of thepresent invention, the ODI can be recorded and assessed. The recordingcan also be saved for any later review, or verification of the properfunction of the medical accelerator. As illustrated in FIG. 8C, the ODIis recorded at 90 cm, isocenter (or 100 cm), and 110 cm. FIG. 8C alsoillustrated the table in an up or lifted position, at isocenter, and ina down or lowered position.

FIG. 8D illustrates a method of performing rotation or optical QA,according to an embodiment of the present invention. This methodmeasures the accuracy of the rotation of the collimator, and before thedevice of the present invention, this QA measurement was not recorded.To check collimator rotation, a technician directs a light source thatmimics the radiation beam onto the device of the present invention,which is disposed on the patient couch. The technician rotates thecollimator to observe that the light moves correctly about the isocenterof the medical accelerator. As illustrated in FIG. 8D, the rotation ofthe collimator is measured about the isocenter (100 cm). Rotation of thecollimator is measured at rotations of 90, 180, 270, and 360 degrees.Using the device of the present invention, the position of the lightsource can be recorded, as illustrated in FIG. 8D.

FIG. 8E illustrates a method of performing optical and radiationcoincidence of a field shaped by the multi-leaf collimator. Asillustrated in FIG. 8E, the device of the present invention can be usedto record not only a light field shaped by the multi-leaf collimator,but also a radiation field shaped by the multi-leaf collimator. Furtheras illustrated in FIG. 8E the coincidence of the light field and theradiation field can be superimposed with the radiation image in order toensure accuracy of the radiation field. The recorded images can be keptto show proper function of the medical accelerator. Additionally, likethe methods of measurement of QA discussed with respect to FIGS. 8C and8D, the method of performing optical and radiation coincidence has notpreviously been recorded.

Additionally, software can be incorporated into a system of operatingthe present invention. Incorporating software would allow the presentinvention to be further automated, saving even more time for a medicalphysicist performing QA on a medical accelerator. The device of thepresent invention can include a microprocessor, computing device, orother means of providing computer control to the device known to orconceivable by one of skill in the art. Alternately, the software can beloaded onto a separate computing device, server, or remote server andcan communicate wirelessly or with a wired connector to a control devicehoused in the device of the present invention. Such a set-up would allowfor multiple QA devices to be controlled by one separate computingdevice, server, or remote server. Any other software control set-upknown to or conceivable by one of skill in the art could also be used.The device can also include robotic control to translate movementcommands from the computer program into movement of the device.Additionally, the operation of the device can be integrated with theoperation of the medical accelerator

For instance, as far as mechanical features, the software can be used tocontrol or measure at least the colinearity and convergence of thelasers, table movement and optical distance indicator, as well ascollimator movement. With respect to radiation features, the softwarecan be used to control or measure at least light and radiation fieldcongruence, radiation profile constancy, and energy constancy. The lightand radiation field congruence can be controlled at least with respectto the x-ray beams, flatness and symmetry, and conformity index. Theradiation profile constancy can be controlled at least with respect toelectron beams, and the energy constancy can be controlled at least withrespect to x-ray and electron beams.

Another software tool can be configured for setting the camera. Inperforming a QA analysis, the technician can use the software to set thecamera, including but not limited to setting the time of integration anda number of frames to be acquired. The settings can be stored as a filein order to streamline QA testing further. For instance, settings foroptical related QA testing can be stored as a file, while settings forradiation related QA testing can be stored as a separate file. When thetechnician is ready to engage in either QA testing protocol, he can usethese stored software files to configure the camera to the appropriatesettings for the type of testing. These settings files can be dated, sothat the technician knows which file is most recent. The file can alsobe called up on the computing device in order to allow the technician toview and verify the settings when the file is called up for view on ascreen of the computing device.

The software can also be configured to control image acquisition.However, if desired the technician can still manually acquire imagesusing the camera. In an exemplary image acquisition, the technician canselect the setting file, described above, acquire an image, and namethat image to save it to a hard drive or networked drive of thecomputing device. After the image is named and saved, it can remain onthe screen, such that the technician can complete various analysis tasksusing the software.

For simple, efficient and effective image analysis purposes, thesoftware can be configured to display a hard coded digital image scale,as illustrated in FIG. 9. The digital image scale can be superimposedover the acquired image, and the technician can also have the option ofturning the digital image scale.

FIG. 10 illustrates an analysis tool, provided by the software controlprogram for the device of the present invention. As illustrated in FIG.10 the analysis tool can drop a circle 400 having a diameter of 10pixels, at a point of interest in the image acquired using the device ofthe present invention. The pixel location of interest can also berecorded using the software control program, per requirements forvarious QA tasks. It should be noted that the diameter of the circle canbe any number of pixels found suitable to one of skill in the art.

FIG. 11 illustrates a localization tool, provided by the softwarecontrol program for the device of the present invention. As illustratedin FIG. 11 the localization tool can drop a first circle 500 having adiameter of 10 pixels. The localization tool then allows the technicianto drag a line 502 to a second point of interest, where a second circle504 can be dropped. In order to adjust the placement of the analysistool, the line 502 can be stretched or shrunk. The software program canthen be configured to determine and display the number of pixels definedby the line. If scale is available, the software program can be used toshow the length of line 502 in mm.

FIG. 12 illustrates a region of interest tool, provided by the softwareprogram for the device of the present invention. The region of interesttool 600 can take the form of a square with crosshairs 602. Preferably,the region of interest tool 600 is 20 or more pixels in diameterdepending on the camera resolution, to be roughly 5 mm. However, theregion of interest tool can be configured to take any other suitablesize known to or conceivable by one of skill in the art. The region ofinterest tool 600 can be a drag and drop tool, such that the techniciancan move it around to various regions of the image. Related tools couldinclude an option to select pixels at the intersection of thecrosshairs. Image statistics could also be calculated, such as meanpixel intensity and standard deviation. Additionally, the software canbe configured to store user name and date on the image and also anyspecific information regarding pixel coordinates and statistics.

FIG. 13 illustrates an exemplary screen for defining scale in anacquired image taken using the device of the present invention. In theexample, the technician acquires an optimal image 700 applies thedigital image scale 702 described with respect to FIG. 9, and sets up adigital scale image. The technician can then call up a ruler tool todraw out a line 704. When the rule tool is called up, a dialog box canopen, requesting a distance of the line in mm. The technician canconfirm the distance, and the program calculates the scale in mm/pixel.The program can also be used to date and store the scale image. Thescale created using this process is considered the default until it isremeasured and updated.

FIG. 14A illustrates an example of a program feature to superimposeimages taken with the device of the present invention. A “superimpose”function key retrieves n number of images and superimposes the images onone another, as illustrated in FIG. 14A. More particularly, FIG. 14Aillustrates an example with two laser images superimposed with a rulerimage map. FIG. 14B illustrates an exemplary recording of laser QA toanalyze the co-linearity of the laser, using the device of the presentinvention. If the lines of the laser in the image form a straight line,the medical accelerator receives a pass, but if they do not the medicalaccelerator receives a fail.

FIGS. 15-19 illustrate exemplary recordings of laser QA tasks executedwith the device of the present invention. For instance, FIGS. 15 and 16Aillustrate acquiring left and right lateral laser QA with the device ofthe present invention. The technician can select Laser QA tasks from adrop down menu. The Laser QA tasks list then includes options to performQA for the left side of the room, the right side of the room, theceiling of the room, and the back wall of the room. For left and rightlateral QA, the program instructs the technician to acquire an image ofa laser at the isocenter. The technician then localizes the lasercrosshair using the pixel analysis tool described with respect to FIG.10. The technician can then name and store the image. The technician isthen prompted to acquire a second laser image after moving the treatmentcouch approximately 10 cm towards the laser. The technician thenacquires a second image of the laser, and localizes the laser crosshairusing the pixel analysis tool. This image is also named and stored. FIG.16B illustrates an exemplary embodiment of the user interface showingthe acquisition of a right room laser QA, as described with respect toFIG. 16A.

FIGS. 17 and 18 illustrate obtaining ceiling and back wall lateral laserQA, respectively, using the device of the present invention. In theseexamples, the technician acquires an image of the ceiling and the backwall lasers at isocenter. For FIG. 17, the technician localizes thelaser cross-hairs and names and stores the ceiling laser image. Thetechnician can then localize the intersection of the back wall andceiling lasers, as illustrated in FIG. 18. The technician can thenacquire another image after moving the treatment couch up toward theceiling by 10 cm. The localization, naming, and storing procedures canbe repeated for this image.

FIGS. 19 and 20 illustrate laser alignment analysis using the device ofthe present invention. The technician can request that the programperform laser analysis using the program menu. The program with combineisocenter locations for all laser crosshairs in a 2D or 3D view. Theprogram will denote the lasers as a pass, if they are contained within a2 mm diameter, as illustrated in FIG. 19. The program then derivesco-linearity for each laser direction from the paired laser images, asillustrated in FIG. 20. The program will denote the lasers as a pass ifthe line is contained within a 2 mm diameter cylinder orthogonal to theisocenter over 20 cm.

FIGS. 21A-F, 22A-F, and 23A-C illustrate exemplary recordings of tablemovement and optical distance indicator (ODI) QA tasks executed with thedevice of the present invention. FIGS. 21A-F relate to QA for tablevertical movements captured using the device of the present invention.The program can be used to set the QA box to horizontal to acquire anODI image at 110 cm SSD, as illustrated in FIG. 21A. The box can also beset manually and the images processed using the program. The QA box isthen rotated vertical 90° to acquire a left or right laser image at 110cm SSD as illustrated in FIG. 21B. This procedure is repeated for 100 cmSSD as illustrated in FIGS. 21C and 21D and 90 cm as illustrated inFIGS. 21E and 21F. The images can all be named and stored. Thesuperimpose function, described above with respect to FIG. 14, can beused to measure vertical distance of the localized laser against thedigital scale. The ruler tool can also be used. The program will denotethis QA as a pass if the distance delta is within 1 mm.

FIGS. 22A-F relate to QA for table lateral movements executed with thedevice of the present invention. The program can be used to set the QAbox horizontal to acquire the optical field image at 100 cm SSD, asillustrated in FIG. 22A. The box can also be set manually and the imagesprocessed using the program. The technician also needs to acquire animage of the ceiling laser as illustrated in FIG. 22B. The proceduresare repeated for a table move 10 cm to the left of center, asillustrated in FIGS. 22C and 22D and 10 cm to the right of center, asillustrated in FIGS. 22E and 22F. The superimpose function, describedabove with respect to FIG. 14, can be used to measure vertical distanceof the localized laser against the digital scale. The ruler tool canalso be used. The program will denote this QA as a pass if the distancedelta is within 1 mm.

FIGS. 23A-C illustrates visual results of table rotation QA, using thedevice of the present invention. The QA box is set horizontal at theisocenter of the medical accelerator, either manually, or using theprogram. Optical images of the light field are acquired at tablerotations of 180°, 90°, and 270°, as illustrated in FIGS. 23A-C,respectively, or any arbitrary but known angles. The crosshairs arelocalized in each image and the image is tagged and stored. The imagescan be superimposed using the feature discussed with respect to FIG. 14.The localized crosshairs must be within a circle of a 2 mm diameter inorder for the system to pass this QA analysis.

As illustrated in FIGS. 24A-D collimator rotation QA is executed in muchthe same manner as table rotation QA, using the device of the presentinvention. The QA box is set horizontal at the isocenter of the medicalaccelerator, either manually, or using the program. Optical images ofthe light field are acquired at collimator rotations of 180°, 0°, 90°,and 270°, as illustrated in FIGS. 24A-D, respectively, or any arbitrarybut known angles. The crosshairs are localized in each image and theimage is tagged and stored. The images can be superimposed using thefeature discussed with respect to FIG. 14. The localized crosshairs mustbe within a circle of a 2 mm diameter in order for the system to passthis QA analysis.

FIGS. 25A-D, 26, 27A and 27B, and 28A and 28B illustrate the visualresults of radiation and light field congruence QA, using the device ofthe present invention. For general radiation field acquisition, whichcan be executed manually or using the device control program, theradiation camera setting is selected to acquire dark current image withthe camera shut for 15 sec or 3×15 sec. Radiation exposure is acquiredfor the same exposure setting and camera-lens non-uniformity correctionis applied if applicable. A mean dark current image can be subtractedfrom the “corrected” mean radiation image.

Particularly, as illustrated in FIGS. 25A-25D a radiation/light fieldcongruence tool can be used to produce images similar to the examplesshown in FIGS. 25A and 25B. The optical camera setting is selectedeither manually or using the device control program, in order to acquirea light field at preset dimensions, such as 20 cm×20 cm. A previouslystored image can also be used. The program can then be used to detect alight field boundary. The radiation camera setting is used to acquireand process dark current and a radiation field for the same dimensions.Radiation field boundary can then be detected at an intensity level of50%. The light field boundary and the radiation field boundary can thenbe overlaid and the image named and stored. FIG. 25C illustrates anexemplary embodiment of the user interface showing the acquisition of a6 MV x-ray QA, as described with respect to FIGS. 25A and 25B. FIG. 25Dillustrates another example of a light field and radiation fieldcongruence image acquired using the device of the present invention.

FIG. 26 illustrates a graph obtained using a profile tool in the controlprogram for the device of the present invention. In order to use theprofile tool a radiation image must be obtained. The program can then beasked to display a 1D plot of x- or y-profiles, such as the graph ofFIG. 26. The light field boundaries 600 can also be displayed on thegraph. The graph can be used to calculate flatness, symmetry, anduniformity index according to formulae. The graph and results can bestored for future reference.

FIGS. 27A and 27B illustrate exemplary plots to show calculation methodsfor determining photon beam flatness and symmetry using a 1D plot, likethe one illustrated in FIG. 26. The photon beam flatness (F) calculationis illustrated in FIG. 27A, whereF=100*(D_(max)−D_(min))/D_(max)+D_(min)). The symmetry (S) calculationis illustrated in FIG. 27B, whereS=100*(area_(left)−area_(right))/(area_(left)+area_(right)). The graphand results can be stored for future reference.

FIGS. 28A and 28B illustrate visual representations of radiationmeasurements taken using the device of the present invention. FIG. 28Aillustrates a visual representation of the radiation field, and FIG. 28Billustrates a calculation of the uniformity index (UI), whereUI=(area₉₀%)/(area₅₀%). The graph and results can be stored for futurereference.

FIG. 29 and FIGS. 30A and 30B illustrate visual representations ofradiation field acquisition and analysis. It should be noted that whenradiation fields are imaged using the device of the present system, asimultaneous film measurement can also be taken. The ratio of the filmmeasurement to the measurement from the camera of the device of thepresent invention can then be used to provide a one-time correction mapthat can be used for every test measurement. More particularly, FIG. 29illustrates a visual representation of a mean radiation image, takenusing the device of the present invention. The device can measure anyradiation field such as 4, 6, 8, 10, 15, or 18 MV x-rays or 6, 8, 1-,12, 15, and 18 MeV electron beams. Dark current and radiation images areacquired according to the protocols described above. The images are thenprocessed by the program to create a mean radiation image. The image canbe named and stored for further reference or additional calculationssuch as flatness, symmetry and uniformity index, all describedpreviously.

FIGS. 30A and 30B illustrate exemplary visual representations of energychecks for radiation analysis. To perform the energy checks thetechnician acquires a pair of appropriate mean radiation images takenunder different thicknesses of a material such as plastic or simulatedsolid water. A region of interest is placed at a center of the radiationimage such as Reading 1 (R1) and Reading 2 (R2) in FIGS. 30A and 30B.R1=the average count for the region of interest for the first image, andR2=the average count for the region of interest for the second image.The energy constant ratio=R1/R2. These results can also be named andstored for future use or reference.

FIGS. 31, 32A-B, and 33A-B illustrate visual representations andanalysis of multi-leaf collimator (MLC) QA measurements, taken using adevice of the present invention. These analyses ensure MLC positioningaccuracy using garden fence delivery, and leaf speed accuracy. Withrespect to FIGS. 31 and 32A-B, which illustrate visual representation ofgarden fence analyses, a garden fence image is acquired by setting anintegration camera time to 30 sec or more. Imaging begins and thetechnician drives a slit beam, formed by X1, X2 MLC in the step andshoot mode to deliver radiation to known positions in the field. Afterdelivery and imaging is stopped the positional accuracy of the leaf gapcan be analyzed, as in FIGS. 31, and 32A-B.

FIGS. 33A and 33B illustrate visual representations of measurement andanalysis for leaf speed of the MLC. An image is acquired by setting anintegration camera time to 30 sec or more. Imaging begins and thetechnician drives each leaf pair with different speeds across the fieldto deliver different doses for each leaf pair. After delivery andimaging is stopped the positional accuracy of the dose profile can beanalyzed, as in FIGS. 33A-B.

The above described software tools for automating the QA process andanalyzing the images taken with the device of the present invention areexemplary and are not to be considered limiting. Many other softwaretools could be developed to further automate the process and provide foranalysis of the images. The control program for the present inventioncan also be configured to produce a report outlining all of the QAmeasurements executed and the results of those measurements.

FIG. 34 illustrates an ion chamber for use with a device for QA of amedical accelerator, according to an embodiment of the presentinvention. The ion chamber 800 can take the form of sheets of plasticwater 802 positioned on a surface of the device 804. The sheets ofplastic water 802 can be up to 10 cm thick. Additionally, one sheet caninclude a receptor 806 for an ion chamber 808. (There are no numberingin the Figure) The receptor 808 can be drilled at a 45° angle to a x-yaxis of the chamber 800. This configuration allows for TG51 calibrationto be performed.

Although the present invention has been described in connection withpreferred embodiments thereof, it will be appreciated by those skilledin the art that additions, deletions, modifications, and substitutionsnot specifically described may be made without departing from the spiritand scope of the invention as defined in the appended claims.

1. A device for unifying comprehensive real-time mechanical anddosimetric quality assurance measurements in radiation therapy,comprising: an imaging surface for receiving multiple energy sources,said imaging surface being positioned on a same plane as an isocenter ofa medical accelerator and wherein the imaging surface is configured torotate about an axis through the isocenter of the medical accelerator,and wherein the multiple energy sources comprise optical light sourcesand radiation fields; a camera for measuring and recording data relatedto the multiple energy sources, wherein the camera is stationary withrespect to the imaging surface; and a mirror system for directing themultiple energy sources to the camera and said mirror system also beingconfigured to maintain an imaging plane of the camera at the isocenterof the medical accelerator, and wherein the mirror system is configuredto rotate about the axis through the isocenter of the medicalaccelerator.
 2. The device of claim 1, wherein the camera is stationaryand positioned to be on the same axis as the imaging plane.
 3. Thedevice of claim 1, further comprising a computer system for collectingand analyzing the data.
 4. The device of claim 3, wherein the computersystem includes a feedback loop for automatic control of the device. 5.The device of claim 1, wherein the measurements are made in real-time.6. The device of claim 1, wherein the mirror system includes no mirrorsor one or more mirrors for directing the energy sources to the camera.7. The device of claim 6, wherein the one or more mirrors are fixed. 8.The device of claim 6, wherein the one or more mirrors are movable. 9.The device of claim 1, wherein the imaging surface is rotatable about anaxis of the camera.
 10. The device of claim 1, where a single phosphorscreen or plastic scintillator sheet will be used for receiving multipleenergy sources from x-ray, electron, light and laser beams
 11. Thedevice of claim 10, wherein the phosphor screen or plastic scintillatorsheet includes markings for spatial calibration.
 12. The device of claim1, wherein said mirror system is rotatable to capture data fromdifferent gantry angles.
 13. The device of claim 1, wherein the deviceis programmed to move in synchrony with mechanical components of themedical accelerator about the isocenter.
 14. The device of claim 1,wherein the camera comprises a conventional camera.
 15. The device ofclaim 14 wherein a mirror is arranged to shield the camera fromradiation.
 16. The device of claim 1 wherein the camera comprises aradiation resistant camera.
 17. The device of claim 1 wherein the cameracomprises a flat panel detector.
 18. The device of claim 1 furthercomprising a computing device configured to control the movement of thedevice.
 19. The device of claim 18 wherein the computing device isprogrammed to automate a QA protocol to be executed using the device.20. The device of claim 18 wherein the computing device is configured toautomate the movement of the device in conjunction with a movement ofthe medical accelerator.
 21. The device of claim 1 further comprising atleast one sheet of plastic water.
 22. The device of claim 21 wherein theat least one sheet of plastic water can accommodate an ion chamber. 23.The device of claim 21 wherein the at least one sheet of plastic watercomprises a receptor for the ion chamber drilled into the at least onesheet of plastic water at a 45° angle.
 24. A method for real-timemechanical and dosimetric quality assurance measurements in radiationtherapy, comprising: providing an imaging surface for receiving multipleenergy sources, said imaging surface having an imaging plane positionedon a same plane as an isocenter of a medical accelerator; directing themultiple energy sources to a camera; and measuring and recording datarelated to the multiple energy sources.
 25. The method of claim 24further comprising the imaging surface taking the form of a phosphorscreen configured to receive all optical light, laser light, andradiation signals.
 26. The method of claim 25 further comprising adigital sensor configured to remain stationary with respect to thephosphor screen.
 27. The method of claim 25 wherein the optical light,laser light, and radiation signals are directed to the phosphor screenvia an optical path.
 28. The method of claim 27 wherein the optical pathfurther comprises mirrors configured to direct the optical light, laserlight, and radiation signals from the phosphor screen to the stationarycamera.